The invention relates to a method and apparatus for the ignition of a hydrocarbon gas stream utilizing a hydrogen pre-ignition arrangement. While the utilization of hydrogen acting on a catalyst to heat the catalyst which in turn heats hydrocarbon gas stream has per se been known in the art (i.e., see U.S. Pat. Nos. 3,518,036 and 3,909,187), previously there has not been a method or apparatus utilizing hydrogen pre-ignition that did not require contact of the catalyst with the hydrocarbon gas stream, and/or utilized hydrogen at low pressure and room temperature (the normal temperature in the surroundings of a conventional gas stove), and/or utilized ambient air for mixture with the hydrogen.
According to one aspect of the present invention, a flame is produced (flame as used herein means a flash and detonation or the like) by the passage of a mix of hydrogen and oxygen-containing gas into contact with the past a Rh/Pt catalyst activated with Al, preferably in gauze configuration. The flame is then directed so that it intersects a hydrocarbon gas stream, igniting the hydrocarbon gas stream. In this way, the catalyst always remains out of the heat of the gas stream and the life of the catalyst is thereby greatly extended. Also, because the particular catalyst, according to the present invention, for use in igniting a hydrocarbon gas stream is used, the hydrogen-air mix may be at room temperature, and need not be heated, resulting in greatly simplified equipment. Since only a small-volume high-velocity stream of hydrogen gas is used for each ignition, the life of the catalyst is even further extended, as is the life of the hydrogen supply whether it be a container with a hydrogen sponge and hydrogen gas at low pressure (i.e., 10 psi), or other suitable conventional structure. The method and apparatus according to the present invention have the advantages of extended catalyst life, extended hydrogen source life, simplicity of components and safety over prior art structures, these advantages making the method and apparatus according to the present invention imminently suited for use with a conventional gas stove in a residential or commercial facility in place of an electric igniter or a pilot light. Since no electrical components need be provided, the invention has still further advantages of simplicity over representative prior art arrangements.
According to one aspect of the present invention, a method of igniting a hydrocarbon gas stream is provided comprising the steps of establishing a flow of hydrogen gas into contact with a 10% Rh/Pt alloy catalyst activated with aluminum and in mesh form to heat the catalyst and establishing a flow of hydrocarbon gas in the vicinity of the catalyst to ignite the hydrocarbon gas with the heated catalyst. The hydrogen gas preferably is at room temperature and a small-volume, intermittent, high-velocity flow from a low-pressure source. According to another aspect of the present invention, a method of igniting the hydrocarbon gas stream utilizing a conduit confining a hydrocarbon gas stream and a hydrogen catalyst at all times disposed out of the hydrogen gas stream, is provided comprising the steps of establishing a flow of hydrogen gas and mixing the hydrogen gas flow with oxygen-containing gas (i.e., ambient air), directing the hydrogen-air gas flow past and in contact with a catalyst to produce a flame extending away from the catalyst, establishing a flow of hydrogen gas through and from the conduit and directing the flame from the catalyst so that it intersects the hydrogen gas stream and ignites the hydrocarbon gas stream.
According to another aspect of the present invention, apparatus for igniting a hydrocarbon gas stream is provided comprising a conduit confining a hydrocarbon gas stream and having a terminal opening through which the gas stream flows, means for establishing a flow of hydrogen gas and mixing the hydrogen gas flow with air, a hydrogen catalyst mounted out of the hydrogen gas stream at all times, means for directing the hydrogen-air gas flow past and in contact with the catalyst to produce a flame extending away from the catalyst and means for directing the flame from the catalyst so that it intersects the hydrocarbon gas stream from the conduit and ignites the hydrocarbon gas stream. The hydrogen handling component, according to the present invention, includes a tubular body member having first and second ends, a tubular inlet extending into the body member first end and received by the body member and terminating within the body member, a gauze configuration catalyst, means for supporting the catalyst within the body member spaced from the termination of the inlet and spaced from the second end of the body member and means defining an opening in the body member between the termination of the inlet tube and the catalyst supporting means. The catalyst preferably comprises a 10% Rh/Pt alloy activated with aluminum in an 80 mesh gauze configuration with 0.003 inch diameter wire forming the gauze. The gauze is preferably planar and is disposed within the supporting means therefor so that the axis of the tubular body member does not intersect the plane of the gauze.
According to yet another aspect of the present invention, an apparatus is provided as a subcomponent for use in hydrocarbon gas ignition assembly, the subcomponent comprising a tube portion having an axis and having an interior shoulder formed therein, a substantially planar catalyst gauze disposed in the tube portion so that the plane of the gauze does not intersect the axis, a generally U-shaped non-catalyst metal mesh sandwiched around the catalyst gauze, portions of the mesh abutting the interior shoulder and deformed end portions of the tube portions spaced from the interior shoulder along the axis and engaging portions of the metal mesh.
It is the primary object of the present invention to provide a hydrocarbon gas stream igniting method and apparatus with increased simplicity, extended catalyst life and a minimum number of electrical components. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.